/*
* Conditions Of Use 
* 
* This software was developed by employees of the National Institute of
* Standards and Technology (NIST), an agency of the Federal Government.
* Pursuant to title 15 Untied States Code Section 105, works of NIST
* employees are not subject to copyright protection in the United States
* and are considered to be in the public domain.  As a result, a formal
* license is not needed to use the software.
* 
* This software is provided by NIST as a service and is expressly
* provided "AS IS."  NIST MAKES NO WARRANTY OF ANY KIND, EXPRESS, IMPLIED
* OR STATUTORY, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTY OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT
* AND DATA ACCURACY.  NIST does not warrant or make any representations
* regarding the use of the software or the results thereof, including but
* not limited to the correctness, accuracy, reliability or usefulness of
* the software.
* 
* Permission to use this software is contingent upon your acceptance
* of the terms of this agreement
*  
* .
* 
*/
/*******************************************************************************
* Product of NIST/ITL Advanced Networking Technologies Division (ANTD).        *
*******************************************************************************/
package gov.nist.javax.sip.header;

import javax.sip.*;

/**
 * Expires SIP Header.
 *
 * @version 1.2 $Revision: 1.5 $ $Date: 2007/02/12 15:19:22 $
 * @since 1.1
 *
 * @author M. Ranganathan   <br/>
 *
 * 
 */
public class Expires
	extends SIPHeader
	implements javax.sip.header.ExpiresHeader {

	/**
	 * Comment for <code>serialVersionUID</code>
	 */
	private static final long serialVersionUID = 3134344915465784267L;
	
	/** expires field
	 */
	protected int expires;

	/** default constructor
	 */
	public Expires() {
		super(NAME);
	}

	/**
	 * Return canonical form.
	 * @return String
	 */
	public String encodeBody() {
		return encodeBody(new StringBuffer()).toString();
	}

	protected StringBuffer encodeBody(StringBuffer buffer) {
		return buffer.append(expires);
	}

	/**
	 * Gets the expires value of the ExpiresHeader. This expires value is
	 *
	 * relative time.
	 *
	 *
	 *
	 * @return the expires value of the ExpiresHeader.
	 *
	 *
	 */
	public int getExpires() {
		return expires;
	}

	/**
	 * Sets the relative expires value of the ExpiresHeader. 
	 * The expires value MUST be greater than zero and MUST be 
	 * less than 2**31.
	 *
	 * @param expires - the new expires value of this ExpiresHeader
	 *
	 * @throws InvalidArgumentException if supplied value is less than zero.
	 *
	 *
	 */
	public void setExpires(int expires) throws InvalidArgumentException {
		if (expires < 0)
			throw new InvalidArgumentException("bad argument " + expires);
		this.expires = expires;
	}
}
